Retractor

ABSTRACT

The invention is a sternal retractor comprising a pair of arms which one of them has hinch at the proximal part of it with sternum engaging blades thereon and a curved cross bar on which said arms are disposed such that in use the retractor can open the bottom of the sternum more than the top of the sternum to minimize damage and injury to the upper ribs and numbness which sometimes results in the hands of open chest surgery patients. The retractor also has application for other surgical procedures, as well, for the same general purpose of providing an opening of varying size along the length of an incision.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the field of medical surgical tools, and moreparticularly, to retractors for chest surgery.

2. Art Background

In open chest surgery, and particularly for cardiac surgery, the sternumis split with chest saw and is held open by a retractor. The sternum isa short bone in the middle of the chest to which all of the ribs areattached either directly, or indirectly. The ribs attached to the top ofthe sternum are shorter than the ribs attached to the bottom of thesternum. Accordingly, when the chest is opened using the retractor, morestress is placed on the shorter upper ribs than the longer lower ribs,as explained in more detail below. Such stress causes various problemsincluding broken ribs.

Typical prior art retractors, also termed sternal spreading or chestspreading retractors, comprise two elongated metal members, termed arms,with blades disposed thereon to capture the sternum, the arms beingparallel to each other, and a rack or bar with teeth on which the armsare disposed. One of the arms is fixed in position for moving the otherarm along the rack. The prior art retractors opened so that the armsremain parallel with respect to each other throughout their range ofmotion. Accordingly, in use, the sternum was displaced an equal amountalong the entire length of the retractor. Prior art retractors includethose devices which have long blades, short blades, multiple shortblades or bent arms. Also, for pediatric and small patients, a smallsized retractor of the same general configuration as described above maybe used.

One recent prior art device comprises a pair of blades which arepivotable through the plane defined by the blades and the bar connectingthem. This device is intended to provide pressure evenly along theentire sternum and it opens in a generally triangular configuration asopposed to the generally rectangular configuration. However, the devicedoes not provide positive control of the movement of the sternum as itis opened and does not necessarily open the sternum to a desiredposition. The device is described in U.S. Pat. No. 4,627,421 issued toSymbas et al.

Another prior art device described in Chaux et al., U.S. Pat. No.4,852,552 comprises a sternal retractor with blades which rotate in twodifferent axes to permit one portion of the split sternum to be raisedabove the other portion in order to provide access to particularportions of the chest cavity.

It has been observed that as a result of the use of such prior artdevices, that following the surgery, a substantial percentage ofpatients develop a neuropathy in which numbness occurs in their left orright hand, and specifically, in the fourth and/or fifth digits (thering finger and little finger). This numbness usually disappears after awhile, but it has been known to occur for a substantial period of time,and in any event, such numbness is at best annoying to the surgicalpatients. The apparent cause of this numbness is that in opening thechest, the opening of the ribs puts substantial pressure on the lowerbranch of the brachial plexus. The lower ribs are longer and also havemore cartilage which permits them to be spread more easily and with lessrisk than the upper ribs. Also, the lower ribs are not connected to anyneurologically important portion of the plexus.

One method of overcoming this problem of applying excessive pressure tothe upper ribs and the adjacent portion of the plexus has been for thesurgeon to attempt to position the retractor as low as possible so thatthere is minimal pressure on the upper, shorter ribs. However, thisapproach is not particularly desirable because the surgeon is not ableto position the retractor in the most advantageous position forretraction of the chest. The present invention overcomes the foregoingdeficiencies of the prior art devices and methods.

SUMMARY OF THE INVENTION

The present invention is a retractor of the general type found in theprior art with certain improvements therein which eliminate the problemwhich occurs during cardiac or other open chest surgery wherein numbnessof the fourth and fifth digits of the right and/or left hand is causedwhen the chest is opened and held open with the prior art retractors andmethods. The present invention also minimizes the risk of breaking ribs,particularly the shorter ribs, during such surgery.

The present invention comprises a retractor, a specifically a sternalspreader, having two arms with blades disposed on each arm, said armsbeing disposed on a cross bar, sometimes referred to as a rack. Theinvention specifically comprises the cross bar being curved rather thanstraight, as is provided in the prior art. The arms remain generallyperpendicular to the cross bar as they moved along the cross bar closerto and away from each other, but in view of the curvature of the crossbar, one end of the arms is always closer to each other than the otherend of the arms.

Preferably, for an adult sternal spreader, when the end of the armsadjacent with the short ribs is approximately 4 inches apart, the end ofthe arms adjacent the long ribs is approximately 8 inches apart. Alsopreferably, the curvature of the cross bar is approximately 40 degrees.Of course the curvature of the cross bar can be varied considerably, theimportant feature being that the arms spread apart to form a generallytriangularly-shaped opening in the chest as the sternum is spread apart.Any form of attachment means for attaching the arms to the cross bar andmoving the arms along the cross bar may be employed, the preferredsystem comprising a rack and pinion.

It is an object of the present invention to provide a retractor which isstructurally simple and which does not obstruct the surgeon's view ofthe chest cavity, and particularly which does creates the largestpossible viewing area with a minimal amount of trauma to the ribs.

It is another object of the present invention to provide a retractorwhich minimizes injury to the brachial plexus during open chest surgery.

It is another object of the present invention to provide a retractorwhich minimizes the risk of broken ribs, particularly the shorter ribs.

It is another object of the present invention to provide a retractorwhich can be used in a plurality of configurations with the cross barbeing disposed either above or below the surgical area.

It is yet another object of the present invention to provide a retractorwhich can be provided a variety of sizes and curvatures and with avariety in the number of blades, as required.

These and other objects of the present invention are achieved byproviding a retractor which is shown in several presently preferredembodiments in the drawings which are described briefly below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the preferred embodiment of the presentinvention.

FIG. 2 is another perspective view of the preferred embodiment of thepresent invention.

FIG. 3 is a perspective exploded view of the present invention in theconfiguration shown in FIG. 1.

FIG. 4 is a side view of the present invention shown in FIG. 2.

FIG. 5 is a top view of the present invention shown in FIG. 2.

FIG. 6 is a side view of the present invention shown in FIG. 1.

FIG. 7 is a top view of the present invention shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIG. 1, 3, 6, and 7, the retractor 23 of the presentinvention comprises generally a cross bar or rack 22 and a first arm 24(24A, 24 B) and second arm 26. The cross bar 22 has in the preferredembodiment teeth on two opposing surfaces 25 and 27 for reasons thatwill be explained below. The critical element of the present inventionis that the cross bar 22 is curved so that the arms 24 (24A, 24 B) and26 are not parallel to each other when the arms are opened or spreadapart, but are angled outward away from each other as shown in FIG. 1.When the arms are closed and adjacent to each other by medial positionover the hinch 59 at the proximal part of the arm 24 which is stabilizedby spring pin 60 at medial position, they are substantially parallel toeach other thereby facilitating the insertion of the blades in an opensternum. One and possibly, both arms may be moved along bar 22.Preferably, the moving means comprises a pinion 28 driven by handle 30.This arrangement allows the present invention to be installed and toforce the cut portions of the sternum apart. The arms have disposedthereon blades 32 and 33 which are common to prior art chest separatorsand which are adopted to secure the sternum after it is cut. The presentinvention includes the use of blades which are longer than those depictas well as multiple blades on a single arm, and angled arm blades, allof which is well known in the art, and after a short distance openingthe fixed arm will be moved to straight (neutral) position and held inplace by pin spring 60 and continued to the desired opening.

In the configuration shown in FIG. 1, the bar 22 would be disposedcloser to the head of a patient than the abdomen, so that 39 of theblade 32 and end 40 of blade 33 are further apart than ends 41 and 42.Accordingly, in use, the invented retractor positively forces thesternum into a specific angled position dictated by the curvature of thebar 22 and the distance between the arms. In this way the chest openingcan be small at area adjacent the short ribs and larger at the areaadjacent the longer ribs. Thus, while the retractor of FIG. 2, discussedbelow, is disposed with the bar near the abdomen, the retractor in theconfiguration of FIG. 1 would be used so that the bar is disposed nearthe head of the patient. It will be appreciated in this connection thatthe reversible nature of the preferred embodiment of the presentinvention is not a requirement of the invention but is the preferredembodiment for purpose of obtaining multiple uses for a single device.The positioning of the bar can be chosen to provide the best view forthe surgeon in a manner which is well known in the art. In the FIG. 2use of the retractor at the start the fixed arm will be at the lateralposition to have the blades together for initial positioning and afterthe short distance of opening it will be moved to straight (neutral)position and held by pin and spring for the rest of opening to thedesired opening position.

In FIG. 3 hinch of the arm and spring pin mechanism 52, 53, 54, 55, 56,57, 58, 59 and 60 are shown.

Referring to FIGS. 2, 4, and 5, the retractor 10 of the presentinvention comprises generally a cross bar or rack 12, and a first arm 14(14A, 14 B) and pin spring 60 and second arm 16. The cross bar 12 has inthe preferred embodiment teeth on two opposing surfaces 15 and 17 forreasons that will be explained below. The critical element of thepresent invention is that the cross bar 12 is curved so that the arms 14(14A, 14B) and 16 are not parallel to each other when the arms opened orspread apart, but are angled either outward away from each other asshown in FIG. 1 or inward toward each other as shown in FIG. 2 asdescribed above. When the arms are closed and adjacent to each other, bylateral position of the arm over the hinch 59 or medial position of thearm over the hinch 59 so that they are substantially parallel to eachother thereby facilitating the insertion of the blades in an opensternum and after a short distance opening the arm will be moved tostraight (neutral) position along the arm and held in place with springpin 60 and opened for the desired position. One and possibly both armsmay be moved along bar 12. Preferably, the moving means comprises apinion 18 driven by handle 20. This arrangement allows the presentinvention to be installed and to force the cut portions of the sternumapart. The arms have disposed thereon blades 19 and 21, which are commonto prior art chest separators and which are adapted to secure thesternum after it is cut. The present invention includes the use ofblades which are longer than those depict as well as multiple blades ona single arm, all of which is well known in the art.

As is further shown in FIGS. 1, 3, 6 and 7, the bar 22 comprises teethon sides 25 and 27 and arms 24 (24 A, 24 B) and 26 have blades 32 and 33respectively. Arms 26 has pinion 28 and crank 30, and as shown, haslocking pin 31 which screws into hole 51 to secure the arm in the desireposition. Arm 24 (24 A, 24 B) has locking pin 29 which secures it inplace as well by screwing into hole 50 and impinging on the bar 22.Pinion 28 comprises individual teeth 44 adapted to mate with the teethon bar 22 so that the arm 26 can be cranked open to spread open thechest. The locking pin 29 provides the arm 24 (24 A, 24 B) with a meansfor disconnecting said arm 24 (24 A, 24 B) from said bar 22 so that thearms can be reversed if desired to the configuration of FIG. 1, toextend in the direction of the curve of the bar if it is desired tolocate the bar above the surgical area rather than below it. Similarly,arm 26 can be removed from bar 22 so that it can be reversed in theconfiguration of FIG. 1. Bar 22 is provided with a flattened area 43onto which arm 24 (24 A, 24 B) may be secured. Arms 24 (24 A, 24 B) and26 have slots 49 and 46, respectively, in which the bar 22 may bedisposed in use.

In the preferred embodiment, the bar is approximately 8 inches long, foradult sternal retractors and has a curvature of 40 degrees. Thecurvature of the bar may be regular, that is, with a single radius ofcurvature or it may have multiple radii of curvature along its length toprovide variation in the angle of the blades with respect to each other.The curvature of the bar can be of any desired radius, the preferredcurvature providing an opening of 8 inches at the bottom of the sternumand an opening of 4 inches at the top of the sternum. The blades can beshort, long, multiple or slightly angled to provide the desired secureopening of the sternum.

It will be obvious to a person of ordinary skill in the art that anumber of modifications and changes can be made to the subject inventionwithout departing from the spirit and scope of the present invention,which is defined by the claims appended hereto and all equivalentsthereof.

1. A surgical sternal retractor comprising: a curved flat rack bar having at least one radius of curvature; two elongated arms, each of said arms being mounted near one end thereof to said bar in a non-parallel relation to each other and having at least one blade means disposed at the other end thereof; and pinion means for moving at least one of said arms along the bar with sufficient force to spread the sternum.
 2. The retractor of claim 1 wherein said curved rack bar comprises teeth on at least one side thereof, and said pinion moving means comprises a pinion associated with at least one arm.
 3. The retractor of claim 2 wherein said rack bar comprises teeth disposed on two opposite facing surfaces and wherein said arms may be disposed on said bar in two opposing configurations, one configuration wherein the blades of said arms converge, and one configuration wherein said blades of said arms diverge.
 4. The retractor of claim 1 wherein said bar is curved such that in use in open chest surgery, the blades can open the lower portion of the sternum 8 inches while the upper part of the sternum is open 4 inches.
 5. The retractor of claim 1 wherein said arms are arranged on said bar in a convergent or divergent arrangement.
 6. The retractor of claim 1 wherein said bar has a curvature of approximately 40 degrees.
 7. A sternal retractor for use in open chest surgery comprising: a rack bar having a row of teeth disposed on opposite sides of said bar, said rack bar having a radius of curvature; a pair of spreader arms connected to said rack bar and extending generally perpendicular to said rack bar in a non-parallel relation to each other, said spreader arms being removable from said rack bar, and one of said spreader arms being movable along said rack bar; blade means for engaging and spreading split sternal halves comprising sternum engaging retractor blade means attached to each of said spreader arms; and pinion means for moving said movable spreader arm along said rack bar with sufficient force to spread a sternum.
 8. The sternal retractor of claim 7 wherein said moving means comprises a pinion disposed in said movable spreader arm, said pinion engaging one of said rows of teeth on said rack bar.
 9. The retractor of claim 7 wherein said rack bar is curved such that in use in open chest surgery, the blades can open the lower portion of the sternum 8 inches while the upper part of the sternum is open 4 inches.
 10. The retractor of claim 7 wherein said rack bar has a curvature of approximately 40 degrees.
 11. A method of opening a sternum and retaining said sternum in an open position for chest surgery comprising: cutting open the sternum, providing a sternal retractor comprising: a rack bar having a row of teeth disposed on opposite sides of said bar, said rack bar having a radius of curvature; a pair of spreader arms which one of them has hinch at the proximal part of it with medial or lateral adjustment and stabilization by spring pin or other methods of the stabilization to be able to get close together over the curved bar for initial placement between split sternum and after a short distance opening to be moved to straight (neutral) position for the rest of opening to the desired position connected to said rack bar and extending generally perpendicular to said rack bar, said spreader arms being removable from said rack bar, and one of said spreader arms being movable along said rack bar; blade means for engaging and spreading split sternal halves comprising sternum engaging retractor blade means attached to each of said spreader arms; and pinion means for moving said movable spreader arm along said rack bar with sufficient force to spread a sternum; whereby said the lower portion of said sternum is spread more than the upper portion of said sternum; and actuating said pinion means for moving said movable spreader arm to spread the sternum a desired amount.
 12. The method of claim 11 wherein said rack bar is disposed superior to the sternum and said spreader arms are divergent from said rack bar.
 13. The method of claim 11 wherein said rack bar is disposed inferior to the sternum and said spreader arms are convergent from said rack bar.
 14. The method of claim 11 wherein said rack bar is curved such that in use in open chest surgery, the blades can open the lower portion of the sternum 8 inches when the upper part of the sternum is open 4 inches.
 15. The method of claim 11 wherein said rack bar has a curvature of approximately 40 degrees.
 16. A method of opening a sternum and retaining said sternum in an open position for chest surgery comprising: cutting open the sternum, providing a sternal retractor comprising: a curved flat rack bar having at least one radius of curvature; two elongated arms, each of said arms being mounted near one end thereof to said bar in a non-parallel relation to each other and having at least one blade means disposed at the other end thereof; and pinion means for moving at least one of said arms along the bar with sufficient force to spread the sternum; whereby said the lower portion of said sternum is spread more than the upper portion of said sternum; and actuating said means for moving said movable spreader arm to spread the sternum a desired amount.
 17. The method of claim 16 wherein said rack bar is disposed superior to the sternum and said spreader arms are divergent from said rack bar.
 18. The method of claim 16 wherein said rack bar is disposed inferior to the sternum and said spreader arms are convergent from said rack bar.
 19. The method of claim 16 wherein said rack bar is curved such that in use in open chest surgery, the blades can open the lower portion of the sternum 8 inches when the upper part of the sternum is open 4 inches.
 20. The method of claim 16 wherein said rack bar has a single radius of curvature of approximately 40 degrees.
 21. A retractor with at least one arm having hinch at the proximal part of the arm which is stabilized in position by spring pin or other method available to stabilize it at medial or lateral position for initial opening of the retractor and neutral (straight) position for the rest of the opening of the sternum/chest to the desired position of the opening.
 22. A retractor that can be used in other chest opening beside sternum with uneven desired opening exposure. 